Shock absorber



Dec. 7, 1937. J. MERCER l 2,101,265'v SHOCK ABSORBER Filed Dec. 2e, '1934 2 sheets-sheet 1A Eig?,

I @lz Il? 26 I @EL j Jqn Hera er' l Nv ENTOE Dec. 7, 1937. J. MERClER l 2,101,265

' SHOCK ABSORBER Fid Dec. 26', 1934 2 Sheets-Sheet 2 INVENTQR RM ATTQ.

Patented Dec. 7, 1937 amazes snocx Ansonmm PATENT OFFICE Jean' Mercier, Neuilly-sur- Seine, France Application December 26, 1934, Serial No. 759,204

. In France January 9, 1934 1o claims..

The present invention relates to landing gears for aeroplanes and other shock-absorbers containing fluid, of the type in which a deformable chamber communicates with an auxiliary chamber through one or more conduits which may be closed -by valve devices. The principal object of-the invention consists in closing olf the connection between the deformable chamber and the auxiliary chamber when the violence ofthe shock to be absorbed causes, starting from the idle position, an exaggerated relative displacement of the opposite walls of the deformable chamber, then opening the connection when the movement changes in direction, thus diminish- 10 ing the reaction, by allowing the excessive pressure 'of fluid thus produced, to diminish byits expansion into the said auxiliary chamber.

The shock-absorbers according to the invention may be completed by a safety-valve which connects the deformable chamberwith the auxiliary chamber when the pressure reaches a dangerous degree which might occasion mechanical breakage. This aords a shock-absorber which is adapted to absorb, during a very considerable part of its stroke, the maximum energy compatible with the mechanical resistance in question.

The invention 'is particularly applicable to landing devices for airplanes, to the b'uiers of locomotives,- to artillery brakes, to automobile spring systems, etc.

The accompanying drawings represent, by way of example, various forms of execution of. the object of the invention. i Figs. 1 to 6 represent, in longitudinal section, each of, the six forms of execution which will be furtheitidescribed.

In the form of execution shown inFig. 1, a cylinderli is separated from an auxiliary chamber 2 by a partition 3 pierced with an aperture 4 in `which is slidable,.by hard friction, a. tube 5. A piston it adapted to slide in the Acylinder I, is provided with a hollow rod I which ls slidable by easy friction in the tube 5 and comprises at ,45 the upper a flanged part 3. Near the respec tive ends ofithe hollow rod 1 are formed orifices 0 and I0 ada` action of a shock, the piston 5 and the partition 3 y 50 approach one aiiother, the fluid first passes freely from the cylinder I into the chamber 2 through vthe orifice 9, the tube 1 andthe ori'lce I0, but when the amount of the relative displacement between thepartition 3 and the piston 3 reaches astma value, niet orince s is nosed by the'tube Qpted to connect the cylinder I with the auxi1iary,\\chamber 2. When, under the,

5, and thus the fluid can ne longer pass from the cylinder into the auxiliary chamber. I'he fluid is thus compressed in the cylinder I, offering an increasing resistance to the approaching movement between the piston 6 and the partition 5 3. During this movement, the piston 6 makes contact with the tube 5 and thus causes it to move. A safety-valve II, which closes an aperture I2 in the partition 3, provided for the passage of the fluid from the cylinder I into the l0 chamber 2, in case the pressure in the cylinder I should reach an excessive value such as would cause mechanical breakage.

When the device begins to return to the idle position, the orifice 9 is uncovered, and again 15 makes connection between the cylinder I and the chamber 2, vthus preventing a too abrupt separation of the piston 6 and the partition 3, and hence reducing the rebounding action.

Inversely, when the shock has the effect of. 20

separating the piston 6 from the partition 3, the fluid first passes freely from the chamber 2 into the cylinder l after a certain relative displacement between said piston and partition, Vthe orice III is covered by the tube 5, and thus 25 a vacuum of increasing value is produced in the v cylinder I, which acts against the separation of the piston 6. During this separation, the flanged part 3 -makes contact with the tube 5' and thus causes it to move. 'When the device begins to 30 return to the idle position, the orifice II) is uncovered and again makes connection between the cylinder I and the chamber 2, thus reducing the rebounding action.

It is evidently possible to regulate the length 35 of the tube 5 and the distances between the respective orifices 9 and I0, and the piston 6 and ange 8, in vvorder to obtain different' damping effects.

In the example of execution shown in Fig. 2, a 40 cylinder I3 has slidable therein a piston I4 which divides the cylinder into two chambers, whereof one forms the deformable space I5 and the other the auxiliary chamber I6. In an aperture I1 in the piston Il is slidable, by hard friction, a tube Il, which is itself traversed, by easy friction, by a tube I9 pierced at its ends with respective orifices 20 and 2i. The tube i9 may extend as far as the adjacent walls of the cylinder I3, when in the idle position; it may also, when in 5o this position, leave a. certain clearance with reference to these adjacent walls, as shown in the figure. A safety-valve 22 provides a connection between the chamber I5 and the chamber I6 in serves the same purpose as the safety-valves Ii slidable in the cylinder 23, by means of a hollow rod 23, thus forming three chambers of variable volume 2l, 23 and 23. A tube 33 is adapted to slide by hard friction. in an aperture formed in the piston 25. An orice 3i in the hollow rod 26 serves to make a permanent connection between the end chambers Eiland 23.

When a shock has the edect of driving the' cylinder 23 into the cylinder 25, the chambers 21 and 23 will diminish in volume, whilst the chamber 23. increases in volume. The uid thus passes from the chambers ill and 23 into the chamber 23 through the orice 3i, the' tube 26 and the tube 30. When the amount of the relative displacement between the two cylinders 23 and 24 reaches a stated value, the lower wall of the cylinder 23 closes the lower end of the tube 3D, thus preventing all communication with the chamber 33. The fluid will thus be compressed in the two chambers 21 and 23, so that each of the two end walls of the cylinder 23 will operate on its own account, hence doubling the energy absorbed for a given amount of motion. As the cylinder 23 continues to enter the cylinder 24, the lower wall of this cylinder 23 will carry with it the tube 33, and thus when the device returns to the idle position, the lower end of the tube 33 is at once'uncovered and makes connection with the chamber 23.

A similar action takes place when the initial Shock has the eiect of withdrawing the cylinder 23 from the cylinder 23 while compressing the uid in the chamber 23, until the yupper wall of the cylinder 23 makes contact with the tube 30 while drawing with it this tube 33.

In this case as well, it is possible to regulate the length of the tube 33 in order to obtain different effects of damping. .A safety-valve 32 and 22 of the preceding examples.

In the example of execution shown in Fig. 4, a partition 35, pierced with an oriilce 36, sepa- `rates a cylinder 33 from an auxillarychamber 34. A piston' 31, slidable in the cylinder 33, carries a tube 33 in which is slidable an auidliary' piston 39. urged by a spring 43 towards the orlilce 36, so that the closing member 4I attached to the piston 39 may close this orince 36. In the piston 31 is provided a valve 42 which is urged by a spring 43 and allows the iluid compressed in the cylinder 33 to pass into the tube 39.4 A safety-valve 44 serves the same purpose as the Safety-valves Il, 22 and, in the preceding exlamples. L

When. owing to a shock, the partition 35 approaches the piston 31, the closing member 4| closes the orice 36, and after this time the iluid is compressed in the cylinder 33, thus damping the relative displacement of the partition 35 land the piston 31. 'I'he iiuid compressed in the cylinder .33 raises the valve 42 and enters the tube 33 above the auxiliary piston 39. During the return movement towards the idle position. ther allonges partition 35 is separated from the piston 31, and the auxiliary piston 39 is moved by this piston, together with the closing member 4i, due to the presence of compressed ilud in the tube 33, this fluid being stopped by the valve 42. It will result that when the return movement commences, the orifice 36 will be opened, thus making connection between the cylinder 33 and the auxiliary chamber 34. It will be thus observed that the valve 52 prevents the closing member di from rising rapidly due to the pressure of the spring 43 during the return` movement. The damping eiect can also be regulated by the distance allowed between the closing member tl and the-orifice 3,6, in the idle position. lThe compressed duid above the piston 39 may return slowly into the cylinder 33 due to the slight clearance between the member il and the piston 31.

In the preceding forms of execution, the closing member is controlled directly by one of the opposite walls of the deformable chamber, it being secured to this wall. However, the closing member-may also be operated without being directly controlled by the opposite walls' `of the deformable chamber.l The example of execution.' Fig. 5, shows a device in which the closing member is operated by the pressure produced in the interior of 'the deformable chamber. A partition il separates the cylinder 45 from the auxiliary chamber 46. In this partition is formed a conduit 63 which may be closed by a slide-valve 49 subjected to the pressure of a spring 53. In the idle position, the spring 5l) urges the valve 49 into the position shown in Fig. 5, so as to leave the connection freeibetween the cylinder 45 and' the chamber 46. A valve 5i is normally urged by a spring 52 against a lower seat 53 formed in the partition 41, but this valve may be driven against the upper seat 54 when the pressure in the cylinder 45 suiiiciently exceeds the pressure in the chamber 46. A conduit 55 is employed, when the valve 5i is raised, to circulate the compressed iluid from the cylinder 45 to a point below the valve 49, thus bringing this valve into the conduit 43 and closing the latter. A conduit 56 allows the pressure in the chamber 46 to act upon the valve 5i.

When a shock brings the piston 51 near the partition 41, the pressure in the cylinder 45 rises more rapidly than in the chamber 46, owing to the loss of pressure occurring in the conduit 48.

value, the valve 5I opens and the fluid compressed in the cylinder 45 is discharged through the conduit 55 yand raises the valve 49, thus closing the conduit 43. During the return movement, the valve 5I drops upon its seat 53 under the action of the spring 52, and the slide-valve 43, which is driven back by the spring 53, again makes connection between the cylinder 45 and the chamber 46.

In the example shown in Fig. 6, the cylinder 53 is provided with a partition 59, and on the respective sides of this partition, the pistons 6U and 34, connected together by a rod 62, are slidable in the cylinder 53, forming three chambers of variable volume 63, 64 and 65. A conduit 66 in the rod 62 makes a permanent connection between the end chambers 63 and 65. It is possible. as in the example shown in Fig.4 3, to have the partition 59 traversed, by hard friction, by a tube open at the endswhich would be operated alterlnately by the pistons 63 and 6I, and the operation would in this case be the same as for Fig. 3. In the example represented in Fig. 6, there is When the difference of pressure attains a given discharged -into thus doubling the energy absorbed for a given one of said walls and to open said communicatcompressing means is 'and the slide-valveGS, urged by the spring lagain makes connection between the chamber provided in-the partition 59, in the same m-anner as for the partition 41 shown in Fig. 5, a conduit 61, a slide-valve 68, a spring 69, a valve 10 urged by a spring 1I, and conduits12 and 13.

. When, under the eiect of a shock, the pistons 60 and 6| proceed into the cylinder 58, the iluid in the chambers' B3 and 65 is compressed and is the chamber 6l through the conduits 66 and 61. When the difference of pressure between the chambers 63 and 65, and the chamber 64, attains a given value, the valve 10 opens, and the compressed fluid ows through the conduit 12, thus raising the valve 63 in such way as to close the conduit 61. During the return movement, the valve 1I falls upon its lower seat, 69,

64 and the chambers 63 and 65. In the same manner as in the example shown in Fig. 3, when the slide-valve 68 is in 4tile closed position, each of the two pistons 60 and 6| acts independently,

degree of motion.

It is obvious that the invention is not limited to thel examples of execution above described, and may be the subject of numerous modicaf tions Awithout departing from the principle of the invention.

Having now describe claim as new and desire Patent is: p

1. In a damping device between two elements movable with 'relation to each other and con'- nected by an elastic connection adapted to maintain said elements in aninitial relative position at a predetermined distance from each other when at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination: a container, fluid compressing means provided with two opposite walls operatively connected with said two elements and adapted to be moved towards and away from eachother, communicating means between said container and said iluid compressing means, whereby said fluid adapted to discharge uid into said container and to receive fluid from said container when said elements are moved with relation to each other, and intercepting means adapted to close said communicating means after a predetermined relative displacement between said elements from their initial relative position and to again open said communicating means as soon as said elements are returning towards their initial relative position.

2'. In a damping deviceas claimed in claim 1,

my invention what I .the further feature consisting in the fact that said elements from their initial relative position.-

has brought said intercepting means against the other of said walls and to open said communicating means as soon. as said elements are returning towards their initial relative position.

3. In a damping device as claimed in claim 1, the further feature consisting in said intercepting means comprises an open-ended tube frictionally engaging one of said walls and adapted to close said communicating meanswhen the relative displacement between said elements from their initial relative position has brought said open-ended tube againstthe other of said walls and to opensaid communicating means as to secure by LettersI the fact that soon as said elements are` returning towards their initial relative position.

4. In a damping device between'two elements movable with relation to each other and connected by an lelastic connection adapted to maintain said elements in an initial relative position at a predetermined distance from each other when at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination, a cylinder provided with two transversal walls and connectedrwith one oi said elements, a piston connected with the other of said elements and adapted to be guided between said walls in said cylinder, whereby two chambers are formed in said cylinder on either side of said piston, communicating means between said two chambers,

and an open-ended tube frictionally engaging said piston and adapted to close said communieating means when the relative displacement between said elements from their initial relative position has brought said open-ended tube against lwhen at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination, a cylinder provided with two transversal walls secured on` said cylinder and connected with one of said elements, two transversal partitions connected together and' with the other of said elements and disposed on either side of one of said transversal walls and adapted to be guided by the inner surface of said cylinder, whereby three chambers are formed between said walls and partitions, a conduit affording a permanent communication between the extreme chambers, communicating means between one extreme chamber and the intermediate chamber, and intercepting means adapted to close said `communicating means when the relative dis` at a predetermined distance from' each other when at rest and to kbring again said yelements at the same distance when they have been moved towards and away from each other, in combination: a container, uid compressing means provided with two opposite walls operatively connected with said two elements and adapted to be moved towards and away from each other, communicating means between said container and said fluid compressing means, whereby said iluid compressing means is adapted to discharge iluid into said container and to receive fluid from said container when said elements are moved with relationl -to each other, intercepting means adapted toclose said communicating means after a predetermined relative displacement between said elements from their initial vrelative'pesition and to again open said communicating means as soon as said elements are returning towards their initial relative' position, a conduit between said compressing means and said container and a spring actuated safety valve in said conduit adapted to allow iiuid to ow only from said compressing means into said container.

7. In a damping device between two elements movable with relation to each other and con- -nected byv an elastic connection adapted to maintain said elements in an initial relative position at a predetermined distance from each other when at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination: :duid compressing means comprising two parts, that is a cylinder connected with one of said elements and a piston connected with the other of said elements and adapted to be guided VVin said cylinder, a container, communicating means between said container and said uid compressing means, intereepting means frictionally engaging one of said parts and a stop surface on the other of .said parts adapted to cooperate with said intercepting means and to close saidcommunicating means when said elements are displaced from their initial relative position and to again open said communicating means as soon as said elements are returning, towards their initial relative position.

8. In a damping device between two elements movable with relation to each other and *connected by an elastic connection adapted to maintain said elements in an initial relative position at a predeterminedv distance from each other when at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination, 'a container, iiuid compressing means provided with two opposite walls operatively connected with said two elements and adapted to be moved towards and away from each other, communicating means between said container and said uidcompressing means, whereby said :duid compressing means are adapted to discharge uld into said container and to receive uid from said container when said elements are moved with relation to each other, intercepting means carried by one of said opposite walls and adapted to close said communicating means when 'the relative displacement between said elements from 'their initial Vrelative position exceeds a. predetermined length, and stop surf on the other of said walls adapted to bee ed by 4said intercepting means, vwhereby d intercepting `means are brought into the Acepting means in `the pressure in 9. In a damping device between two elements 1 movable with relation to each other and connected by an elastic connection adapted to maintain said elements in an initial relative position at a predetermined distance from each other when at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination, acontainer, uid compressing means provided with two opposite walls operatively connected with said two elements and adapted to be moved towards and away from each other, an open-ended tube frictionally engaging one of said wall, a second tube with closed ends slidingly engaging said open-ended tube and carried by the other of said walls and provided near its ends on its lateral surface with apertures adapted to be covered and uncovered by said open-ended tube, and stop surfaces at the ends of said second tube adapted to be engaged by the ends of said open-ended tube.

y 10. In a damping device between two yelements movable with relation to each other and connected by an elastic connection adapted to maintain said elements in an initial relative position at a predetermined distance from`each other when at rest and to bring again said elements at the same distance when they have been moved towards and away from each other, in combination, a container, fluid compressing means provided with two opposite walls operatively connected with said two elements andadapted to be moved towards and away from each other, communicating means between said container and said fluid compressing means, whereby said uid compressing means are adapted to discharge fluid into said container and to receive uid from said container when said elements are moved with relation to each other, intercepting means adapted to open and to close said communicating means, guiding means for said intercepting means, yielding means adapted to urge said intercepting means in the open position, a conduit between said compressing means and said guiding means adapted to allow uid from said compressing means to urge said interthe closed position, and spring actuated valve means normally inserted in said conduit and adapted to release said conduit when said compressing means exceeds a predetermined value. y

JEAN MERCIER. 

